Saketh

We use ReportLab for exporting to PDF from Notalon. The Python API is clean, and exposes just enough lower-level details to be flexible in formatting. Plus, it works without issues on all major platforms.

We use wxPython for Notalon's GUI, and the ease of development has been amazing. With wxPython, we have a note-taking application for students within 2000 LOC. For our needs, it's perfect.
It also helps that the resultant code is the most Pythonic out of the GUI toolkits we evaluated.